Means for adjusting the amount of damping liquid supplied to an offset printing machine

ABSTRACT

THE DAMPING LIQUID IS TRANSFERRED FROM AN IMMERSION ROLLER TO A DAMPING ROLLER BY MEANS OF A TRANSFER ROLLER, PERFORMING A ROCKING MOVEMENT BETWEEN BOTH ROLLERS. THE TRANSFER ROLLER IS MOUNTED IN BRACKETS SUPPORTED PIVOTABLY ON A SHAFT, WHICH ITSELF IS ROTATABLY MOUNTED IN THE SIDE WALLS OF THE MACHINE. A TWO-ARM LEVER IS FREELY MOUNTED ON THE SHAFT, AND HAS ON ITS EXTREMITY A ROLLER ENGAGING WITH THE CIRCUMFERENCE OF A CAM ROTATING AT A SPEED DIFFERENT FROM THAT OF THE IMMERSION ROLLER. ADJUSTABLE STOP MEANS ALLOW AN ADJUSTMENT OF THE POSITION OF   THE TRANSFER ROLLER WITH RESPECT TO THE IMMERSION ROLLER AND THE DURATION OF THEIR CONTACT.

Oct. 26, 19-71 J. JuRNY 3,614,927

' MEANS FOR ADJUSTING THE AMOUNT OF DAMPING LIQUID k SUPPLIED TO AN OFFSET PRINTING MACHINE Filed June 30, 1969 v 2 Sheets-Sheet! INVENTOR JEJe/ fawn c7 BY WM K y k Oct. 26, 1971 J. JURNY 3,614,927

MEANS FOR ADJUSTING THE AMOUNT OF DAMPING LIQUID SUPPLIED TO AN OFFSET PRINTING MACHINE Filed June 30, 1969 2 Sheets-Sheet E INVEI \I TOR .755 ef fl? United States Patent 1 MEANS FOR ADJUSTING THE AMOUNT OF DAMPING LIQUID SUPPLIED TO AN OFF- SET PRINTING MACHINE Josef Jurny, Sebranice, Czechoslovakia, assignor to Adamovske strojirny, narodni podnik, Adamov, Czecho- Slovakia Filed June 30, 1969, Ser. No. 837,708 Claims priority, application Czechoslovakia, July 1, 1968, 4,821/68 Int. Cl. B411 23/02 US. Cl. 101-148 4 Claims ABSTRACT OF THE DISCLOSURE The damping liquid is transferred from an immersion roller to a damping roller by means of a transfer when performing a rocking movement between both rollers. The transfer roller is mounted in brackets supported pivotably on a shaft, which itself is rotatably mounted in the side walls of the machine. A two-arm lever is freely mounted on the shaft, and has on its extremity a roller engaging with the circumference of a cam rotating at a speed different from that of the immersion roller. Adjustable stop means allow an adjustment of the position of the transfer roller with respect to the immersion roller and the duration of their contact.

BACKGROUND OF THE INVENTION This invention relates to apparatus for the adjustment of the amount of damping liquid supplied for offset p nting machines.

Known arrangements for the adjustment of the amount of damping liquid, supplied to the spreader roll of damping devices take advantage of changes of the angle of rotation of an immersion roller, from which the transfer roller takes a film of liquid solution. The transfer roller transfers a part of the liquid to the distributing roller and to the spreader rollers. As the immersion roller is turned intermittently at low speed, determined by the operation of said device, the liquid film is wiped from its surface. Due to surface tension of the liquid particularly in the course of prolonged printing, and because remnants of transferred ink tend to deposit thereon, undesirable stripes occur on the printed sheets. Thus the liquid film on the immersion roller is generally insufficient and not uniform. There are other arrangements, where the immersion roller is continuously rotated so that a quick uniform transfer of the liquid film is obtained. The transfer roller is continuously pressed against the immersion roller and the amount of transferred liquid is adjusted by changes of pressure of the transfer roller against the immersion roller. Other arrangements use a steadily rotating and eccentrically supported immersion roller. This eccentric support causes the roller to contact a further damping roller and transfer the damping liquid.

A drawback of each of the known arrangements is that the adjustment of the amount of damping liquid is accomplished by changes in the gap between the immersion and transfer roller. This design requires extreme accuracy in manufacture of the rollers, and a great deal of skill in supporting and maintaining their coaxiality and rigidity. A further drawback of said arrangements is the insufficient sensitivity of the adjustment and its high complexity.

It is another object to provide means for continually changing the position of the immersion roller, from which the ink is wiped, in the course of operation so that in the event of back transfer stripes are avoided due to local accumulation.

3,614,927 Patented Oct. 26, 1971 Fee A further object is to maintain an intact film of liquid on the immersion roller during the course of continuous rotation and dipping.

SUMMARY OF THE INVENTION In accordance with this invention the transfer roller is mounted in brackets pivotably supported by a shaft freely rotatably mounted in the side walls of the machine. Spring means force the brackets against stop means fixed on said shaft and spring means act on said shaft and force said transfer roller into engagement with the immersion roller. A two arm lever is freely rotatably mounted on the shaft, with a roller on one of its extremities. The roller engages a cam rotated at a speed difierent from the rotating speed of the immersion roller, to determine in an adjustable manner the extent of contact of the transfer roller with the immersion roller.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of one embodiment in section along the plane AA indicated in FIG. 2,

FIG. 2 is an elevation thereof,

FIG. 3 is a side view of an alternative embodiment in section along the plane BB in FIG. 4,

FIG. 4 an elevation of said alternative arrangement showing an eccentric mounting and drive transmission,

FIG. 5 a detail of the embodiment of the transmission and the cam as shown in FIGS. 3 and 4.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS The arrangement as shown in FIGS. 1 and 2 comprises an immersion roller 1 mounted rotatably in side walls 2 and 3 of the printing machine. A driving sprocket wheel 4 is fixed on the shaft of the immersion roller 1 outside the side wall 3. A cam 6 is provided on the internal side of the side wall 3 and is freely rotatable on the shaft of the immersion roller 1, fixed on gear wheel 7 Which meshes with the larger gear wheel 30. In the alternative arrangement shown in FIGS. 3, 4 and 5 a gear wheel 32 is fixed on the shaft of the immersion roller 1 by means of a bolt 5, said wheel 32 meshing with a gear wheel 33 firmly connected with a cam 6, both rotatably mounted on a stable bolt 31.

The lower part of the immersion roller 1 extends into a dish 29 containing the damping liquid. Fixed on a rotatable shaft 8 are a pair of stops 9 which abut against adjusting screws 10 supported by brackets 11. The shaft 8 is mounted rotatably in the side walls 2, 3 of the printing machine. The brackets 11, having according to FIG. 1 the shape of a two arm lever, are rotatably supported on the shaft 8. The upper extremities are provided with slots, supporting rotatably the transfer roller 12. The adjusting screws 10 of the brackets 11 and the stops 9 are mutually maintained in engagement by tension springs 13 suspended on bolts 14. Adjustment of screw 10 will therefore vary the distance between transfer roller 12 and immersion roller 1 by angularly locating the bracket 11 with respect to the shaft 8. A lever 16 is fixed on the shaft 8 by means of a bolt 15, and is provided on its extremity with an adjusting screw 17 bearing against the lower extremity of one or the other of the two arm levers 18. The lever 18 is rotatably mounted on the shaft 8 and its upper end is provided with a bolt 20 rotatably supporting a roller 19 bearing against the cam 6. A pull or tension spring 21, suspended between a bolt 22 fixed on the lever 16 and a bolt 23 fixed on the side wall 3 generates the required pressure between the roller 12 and the immersion roller 1. The transfer roller 12 transfers the damping liquid from the immersion roller 1 to the damping roller 28. FIGS. 3 and 4 show an alternative arrangement of this control for the regulating elements,

where the adjusting screw 17 is replaced by a set screw 24. Here the shaft 8 is supported at one end in a bracket 25, fixed on the side wall 3 and the two-arm lever 18 is pivotably in the side wall 3 and provided on its extremity with a turning means 27. The described structure operates as follows:

The immersion roller 1 is rotated in a uniform movement by the driving sprocket wheel 4 driven by a chain from a not shown mechanism such as the offset plate roller. According to the alternative arrangement shown in FIGS. 3, 4 and 5 the gear wheel 32 meshes with the gear wheel 33 and is turned simultaneously with the immersion roller 1. The gear wheel 33 is connected with the cam 6, causing by way of the roller 19 a rocking movement of the two-arm lever 18 with a constant stroke. In the arrangement according to FIGS. 3, 4 and 5 the cam 6 has a different number of revolutions with respect to the immersion roller 1 due to a different number of teeth of both gear wheels 32 and 33.

In the arrangement according to FIGS. 1 and 2 the freely rotatably mounted cam 6, receiving its drive from the driving mechanism by way of the gear wheel 8 also has a different number of revolutions with respect to the immersion roller 1.

The rocking motion of the two-arm lever 18 is transmitted by way of the adjusting screw 17 and the lever 16 to the shaft 8, which is thereby turned. This motion is subsequently transmitted by means of the interaction of stops 9 and screws 10 on the brackets 11 which cause a removal of the transfer roller 12 from the immersion roller 1 and the contact with the damping roller 28. The change of amount of supplied damping liquid is accomplished by adjustment of the width of the film of the damping liquid wiped from the immersion roller 1. The width of the strip of the transferred film of damping liquid is determined by the different length and by the different angle, at which the transfer roller 12 is pressed against the immersion roller 1. In the position as shown in FIG. 1 a narrow strip of damping film is transferred, the cam 6 being with respect to the roller 19 in its lowest position. In the course of rotation of the cam 6, the two-arm lever 18 is rocking and as its other extremity bears against the adjusting screw 17 (position I), and an immediate removal of the transfer roller 12 from the immersion roller 1 and pressing against the damping roller 28 is accomplished. If a larger amount of damping liquid is required, the adjusting screw 17 is released so that a clearance is created between the adjusting screw 17 and the lower extremity of the two-arm lever 18. Within this clearance the two-arm lever 18 oscillates freely until it bears against the adjusting screw 17. The transfer roller 12 is for this period pressed against the immersion roller 1 and the transferred strip of the film of damping liquid is widened. In case of complete retraction of the adjusting screw 17 to position II the maximum width of the film of transferred damping liquid is obtained (FIG. 1).

In the alternative arrangement according to FIGS. 3 and 4 the adjustment is achieved not by means of the adjusting screw 17 but by means of eccentric bolt 26. Turning of bolt 26 changes the position of the axis of the twoarm lever 18 creating thus a different clearance between the set screw 24 and the lower extremity of the two-arm lever. The position of the two-arm lever 18 and conse quently also the width of the strip of the damping liquid is thus changed.

What is claimed is:

1. An arrangement for supplying damping liquid to offset printing machines comprising an immersion roller, means for rotating said immersion roller about its central axis, a damping roller mounted for rotation about an axis parallel to the immersion roller and spaced there-l from, a rotatable shaft mounted parallel to the axis of said immersion roller and offset therefrom, a pair of spaced elongated brackets extending between said damping and immersion rollers and rotatably mounted aboutsaid shaft, a transfer roller secured to the end of said brackets for alternate movement into contact with said immersion and said damping rollers upon rocking of said shaft, means for adjustably limiting the rotation of said brackets about said shaft, a first lever fixed radially on said shaft and extending away from said rollers, a second lever rotatable about the axis of said shaft, said second lever having a first arm adjacent to said first lever and a second arm extending away therefrom, means for adjustably fixing said first lever and said first arm at a predetermined distance, a cam mounted about an axis parallel to said shaft, means interposed between said immersion roller and said cam to rotate said cam at a speed different from said immersion roller, a cam follower located at the end of said second arm adapted to engage said cam whereby the rotation of said immersion roller would cause said second lever to periodically rock said shaft and move said transfer roller between said immersion roller and said damping roller.

2. The arrangement according to claim 1 wherein said means for limiting the rotation of said bracket about said shaft comprises a stop secured to said shaft, a screw member mounted on said bracket adapted to abut against said stop and spring means for urging said screw member and stop together.

3. The arrangement according to claim 1, wherein said means for adjustably fixing said first lever and first arm at a predetermined distance comprises a screw member mounted on said first lever and adapted to abut against said first arm and spring means for urging said screw member and stop together.

4. The arrangement according to claim 1 wherein said means for adjustably fixing said first lever and said first arm at a predetermined distance includes means permitting said second lever to be pivoted about an eccentrically rotatable bolt and means for adjusting the angular position of said bolt.

References Cited UNITED STATES PATENTS 1,541,890 6/1925 Banzett 101-147 X 2,165,235 7/1939 Curtis 101148 3,020,840 2/1962 Koch 101350 3,246,601 4/1966 Fischer 10l350 3,301,182 1/1967 Leviton 101351 3,505,952 4/1970 Schnall 10l349 X WILLIAM B. PENN, Primary Examiner E. M. COVEN, Assistant Examiner US. Cl. X.R. 101350 

